Endoscopes are well-known in the art and are commonly used for numerous medical procedures. One exemplary procedure is removing polyps, lesions or other types of targeted tissue from the gastrointestinal mucosal wall of a human subject. Various cauterization devices have been developed to remove polyps. These devices, however, sometimes cause serious thermal injury to the gastrointestinal wall, fail to remove the entire targeted tissue, or do not completely cauterize blood vessels which lead to excessive bleeding. Snare devices designed to encircle and remove polyps often do not capture all of the targeted tissue. Further, a physician may experience difficulty in securing the targeted tissue with the snare. Snaring only the minimal tissue required from the three layer wall, i.e., mucosa, submucosa, and muscularis, is also important. More specifically, to prevent complications, the muscularis tissue should be avoided all together in this type of procedure. In an effort to solve these and other problems, one technique used is a sub-mucosal lift polypectomy, which involves using a needle to inject the tissue with, for example, a saline solution, to lift the tissue to a more favorable position. This technique improves complete transection. The injected fluid separation also insulates the outer muscle from cautery or thermal injury.
Various other endoscopic procedures require a needle, including use of a needle for: washing a targeted work site; applying dies for the purpose of highlighting diseased or abnormal tissue; injecting tattoo medium for post-transection surveillance purposes; and hemostatic injection therapy for post-polypectomy bleeding. In these and other procedures requiring a needle and a second endoscopic device, a physician must use two separate auxiliary instruments, and one at a time feed the devices in and out of the instrument channel of an endoscope, which increases the overall procedure time.
In certain situations, the needle may be combined with a second endoscopic device in one auxiliary instrument having a multiple lumen catheter. However, combining a needle with a second endoscopic device in a multiple lumen catheter can be problematic. For example, the needle may puncture the multiple lumen catheter or deploy beyond a desired length, injuring the patient. Further, radio frequency energy used to energize the second endoscopic device, for example a cauterization snare, may be transferred to other portions of the device, which in turn would direct the current away from the targeted tissue. Also, the incorporation of a needle stop to prevent the needle from falling out of the catheter may result in “lost motion.” If the needle lumen is made large enough to allow the addition of the needle stop, the actuator that is attached to the needle and the needle itself will fit very loosely within the needle lumen, and be free to move within the needle lumen. This type of freedom of movement is referred to as “lost motion” in the art.